/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_mat_sub_q31.c
 * Description:  Q31 matrix subtraction
 *
 * $Date:        18. March 2019
 * $Revision:    V1.6.0
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"

/**
  @ingroup groupMatrix
 */

/**
  @addtogroup MatrixSub
  @{
 */

/**
  @brief         Q31 matrix subtraction.
  @param[in]     pSrcA      points to the first input matrix structure
  @param[in]     pSrcB      points to the second input matrix structure
  @param[out]    pDst       points to output matrix structure
  @return        execution status
                   - \ref ARM_MATH_SUCCESS       : Operation successful
                   - \ref ARM_MATH_SIZE_MISMATCH : Matrix size check failed

  @par           Scaling and Overflow Behavior
                   The function uses saturating arithmetic.
                   Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] are saturated.
 */
#if defined(ARM_MATH_MVEI)
arm_status arm_mat_sub_q31(
	const arm_matrix_instance_q31 *pSrcA,
	const arm_matrix_instance_q31 *pSrcB,
	arm_matrix_instance_q31 *pDst)
{
	uint32_t        numSamples;       /* total number of elements in the matrix  */
	q31_t          *pDataA, *pDataB, *pDataDst;
	q31x4_t       vecA, vecB, vecDst;
	q31_t const   *pSrcAVec;
	q31_t const   *pSrcBVec;
	uint32_t        blkCnt;           /* loop counters */
	arm_status status;                             /* status of matrix subtraction */

	pDataA = pSrcA->pData;
	pDataB = pSrcB->pData;
	pDataDst = pDst->pData;
	pSrcAVec = (q31_t const *) pDataA;
	pSrcBVec = (q31_t const *) pDataB;

#ifdef ARM_MATH_MATRIX_CHECK

	/* Check for matrix mismatch condition */
	if ((pSrcA->numRows != pSrcB->numRows) ||
		(pSrcA->numCols != pSrcB->numCols) ||
		(pSrcA->numRows != pDst->numRows)  ||
		(pSrcA->numCols != pDst->numCols)) {
		/* Set status as ARM_MATH_SIZE_MISMATCH */
		status = ARM_MATH_SIZE_MISMATCH;
	} else

#endif /* #ifdef ARM_MATH_MATRIX_CHECK */
	{

		/*
		 * Total number of samples in the input matrix
		 */
		numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
		blkCnt = numSamples >> 2;
		while (blkCnt > 0U) {
			/* C(m,n) = A(m,n) + B(m,n) */
			/* sub and then store the results in the destination buffer. */
			vecA = vld1q(pSrcAVec);
			pSrcAVec += 4;
			vecB = vld1q(pSrcBVec);
			pSrcBVec += 4;
			vecDst = vqsubq(vecA, vecB);
			vst1q(pDataDst, vecDst);
			pDataDst += 4;
			/*
			 * Decrement the blockSize loop counter
			 */
			blkCnt--;
		}
		/*
		 * tail
		 */
		blkCnt = numSamples & 3;
		if (blkCnt > 0U) {
			mve_pred16_t p0 = vctp32q(blkCnt);
			vecA = vld1q(pSrcAVec);
			pSrcAVec += 4;
			vecB = vld1q(pSrcBVec);
			pSrcBVec += 4;
			vecDst = vqsubq_m(vecDst, vecA, vecB, p0);
			vstrwq_p(pDataDst, vecDst, p0);
		}
		status = ARM_MATH_SUCCESS;
	}

	/* Return to application */
	return (status);
}

#else
arm_status arm_mat_sub_q31(
	const arm_matrix_instance_q31 *pSrcA,
	const arm_matrix_instance_q31 *pSrcB,
	arm_matrix_instance_q31 *pDst)
{
	q31_t *pInA = pSrcA->pData;                    /* input data matrix pointer A */
	q31_t *pInB = pSrcB->pData;                    /* input data matrix pointer B */
	q31_t *pOut = pDst->pData;                     /* output data matrix pointer */

	uint32_t numSamples;                           /* total number of elements in the matrix */
	uint32_t blkCnt;                               /* loop counters */
	arm_status status;                             /* status of matrix subtraction */

#ifdef ARM_MATH_MATRIX_CHECK

	/* Check for matrix mismatch condition */
	if ((pSrcA->numRows != pSrcB->numRows) ||
		(pSrcA->numCols != pSrcB->numCols) ||
		(pSrcA->numRows != pDst->numRows)  ||
		(pSrcA->numCols != pDst->numCols)) {
		/* Set status as ARM_MATH_SIZE_MISMATCH */
		status = ARM_MATH_SIZE_MISMATCH;
	} else

#endif /* #ifdef ARM_MATH_MATRIX_CHECK */

	{
		/* Total number of samples in input matrix */
		numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;

#if defined (ARM_MATH_LOOPUNROLL)

		/* Loop unrolling: Compute 4 outputs at a time */
		blkCnt = numSamples >> 2U;

		while (blkCnt > 0U) {
			/* C(m,n) = A(m,n) - B(m,n) */

			/* Subtract, saturate and then store the results in the destination buffer. */
			*pOut++ = __QSUB(*pInA++, *pInB++);

			*pOut++ = __QSUB(*pInA++, *pInB++);

			*pOut++ = __QSUB(*pInA++, *pInB++);

			*pOut++ = __QSUB(*pInA++, *pInB++);

			/* Decrement loop counter */
			blkCnt--;
		}

		/* Loop unrolling: Compute remaining outputs */
		blkCnt = numSamples % 0x4U;

#else

		/* Initialize blkCnt with number of samples */
		blkCnt = numSamples;

#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

		while (blkCnt > 0U) {
			/* C(m,n) = A(m,n) - B(m,n) */

			/* Subtract, saturate and store result in destination buffer. */
			*pOut++ = __QSUB(*pInA++, *pInB++);

			/* Decrement loop counter */
			blkCnt--;
		}

		/* Set status as ARM_MATH_SUCCESS */
		status = ARM_MATH_SUCCESS;
	}

	/* Return to application */
	return (status);
}
#endif /* defined(ARM_MATH_MVEI) */

/**
  @} end of MatrixSub group
 */
